There are few Arduino based balloon trackers that generate WPSR and APRS
signals. There is an Arduino library called JT8Encode which is the
software behind some of them. This is the entire signal processing from
bytes to RF but easily adapted to insertion at any point in the
processing. Theygenerally just filter the synthesized signal for xmit.
I have one in my backyard with a random wire sending WSPR. It's a
ZackTek WSPR-TX pico. Also have a tinyAPRS-WSPR unit but not using it.
There are some others. The software is open source for most of them.
-73 -
*Rud Merriam K5RUD*
/Mystic Lake Software/ <http://mysticlakesoftware.com/>
On 12/21/20 10:13 AM, Neil wrote:
I've been messing about with a function which exports the tone
parameters and sends them to a UDP program which then programs a DDS.
Not for LF/VLF, this is for a multiplied transmit chain on SHF. The
GFSK transitions in FT8 etc are added later in wsjt-x but for this
lash-up, I took the values from itone and nsym between genft8_() and
gen_ft8wave_() in widgets\mainwindows.cpp and sent then using
QUdpSocket writeDatagram() to a simple receiving server on another
device, which generates the timed sequence by sending commands to a
DDS board. I haven't tried it with QRA64 or JT4 yet.
That approach avoids having to mix anything at signal frequency on 47
or 122 GHz, and permits arbitrary multiplication factors, but you
might be able to use a similar technique to program a DDS at baseband.
A different, more generic approach has been tried by Andy G4JNT. He
takes the audio tones and interprets those into frequencies and sends
the codes to a DDS to reproduce the original. Andy's system is
entirely agnostic about the software using to generate the tones,
where I have to patch in my extract-to-UDP source into wsjt-x.
Very early days, and I'm too tied up with machining radio bits to do
much coding at the moment. However, a new AD9912 DDS board just
arrived....
Neil G4DBN
http://g4dbn.uk
On 12/21/2020 12:25 AM, lstosk...@cox.net wrote:
Seems foolish to build a whole SSB rig to convert the audio signal
from WSJT to RF when at low frequencies some direct synthesis should
be possible. Or am I dreaming?
N0UU
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